Spanning Tree port configuration
By default for STP/PVST+, Spanning tree is turned Off for downlink ports
Spanning tree port parameters are used to modify STP operation on an individual port basis. STP port parameters include:
•Port priority
•Port path cost
The following table describes the Spanning Tree Port Configuration commands.
Table 85 Spanning Tree Port Configuration commands
Command | Description |
Configures the port priority. The port priority helps determine | |
priority | which bridge port becomes the designated port. |
| In a network topology that has multiple bridge ports connected to a |
| single segment, the port with the lowest port priority becomes the |
| designated port for the segment. |
| The range is 0 to 255, and the default is 128. |
| RSTP/MSTP: The range is 0 to 240, in steps of 16 (0, 16, 32...) |
| and the default is 128. |
| Command mode: Interface port |
Configures the port path cost. The port path cost is used to help determine the designated port for a segment. Generally speaking, the faster the port, the lower the path cost.
The range is 1 to 65535. The default is 10 for 100Mb/s ports, and 1 for Gigabit ports. A value of 0 indicates that the default cost will be computed for an
RSTP/MSTP: The range is 1 – 200000000, and the default it 20000 for Gigabit ports.
Command mode: Interface port
Defines the type of link connected to the port, as follows:
auto: Configures the port to detect the link type, and automatically match its settings.
p2p: Configures the port for
shared: Configures the port to connect to a shared medium (usually a hub).
This command only applies when RSTP is turned on. See the “Common Internal Spanning Tree configuration” section for more information.
Command mode: Interface port
[no]
Enables or disables this port as an edge port. An edge port is not connected to a bridge, and can begin forwarding traffic as soon as the link is up. Configure server ports as edge ports (enabled).
This command only applies when RSTP is turned on. See the “Common Internal Spanning Tree configuration” section for more information.
Command mode: Interface port
Enables or disables Port Fast Forward on the port. | |
fastforward | Command mode: Interface port |
Enables STP on the port. | |
| Command mode: Interface port |
no | Disables STP on the port. |
enable | Command mode: Interface port |
show interface gigabitethernet | Displays the current STP port parameters. |
{<port number>} | Command mode: All |
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Configuration Commands 80